Fatal Adverse Events Associated With Programmed Cell Death Ligand 1 Inhibitors: A Systematic Review and Meta-Analysis

Purpose We performed this systematic review and meta-analysis to assess the incidence of fatal adverse events that were associated with the use of programmed cell death ligand 1 (PD-L1) inhibitors, to describe them and to statistically depict factors that were associated with these events. Method PubMed, Embase, and Cochrane Library were completely searched based on the following terms or relevant Medical Subject Heading ones: “atezolizumab”, “durvalumab”, “avelumab”, and “cemiplimab”. Results A total of 26 eligible studies were identified, incorporating 6,896 unique participants. The overall incidence was 1.24% (95% CI: 0.93–1.65%). The incidence and odds were higher in patients with non-squamous non-small cell lung cancer (NSCLC) than those with urothelial carcinoma (2.25 vs. 0.85, p = 0.04), (odds ratio [OR: 2.69; 95% CI: 1.04–6.97, p = 0.04)], higher in the middle-aged group than the young group (1.74 vs. 0.89, p = 0.01), (OR: 2.13; 95% CI: 1.26–3.61, p = 0.01), and higher in the trial phase I than the trial phase II (1.76 vs. 0.60, p = 0.01), (OR: 0.31; 95% CI: 0.13–0.75, p = 0.01). Notably, the trial phase I had a higher incidence than trial phase II or III following regulating for cancer types and average age (OR: 0.28; 95% CI: 0.11–0.71, p = 0.01, OR: 0.48; 95% CI: 0.24–0.95, p = 0.04, respectively). In terms of organ-specific fatal adverse events, interstitial lung disease (ILD) was frequently documented. A variety of respiratory system-related fatal adverse events were recorded, including but not limited to pneumonia and respiratory failure. As for organ-unspecific fatal adverse events, substantial cases of sepsis and neutropenia were recorded. Conclusion This study firstly provided a comprehensive incidence and the spectrum of fatal adverse events associated with PD-L1 inhibitors, and identified three potential susceptible factors of that, yielding a capability for clinicians to distinguish high-risk populations from relatively low-risk ones, and facilitating to improve the safety of PD-L1 inhibitors broadly used in the clinical setting.